Yamaha F115TXR OB 2010 can't get slalom skier up on Hurricane Sundeck 188

[Yamaha115OB]

Hi, I've got a Yamaha F115TXR OB on a Hurricane 188 Sundeck. The engine runs well...5500 RPM, and we can get a skier up on two skis without a problem, but we can't get a skier up on one ski...there just isn't enough power as each skier (who has experience getting up on one ski with other boats), says we don't go fast enough. At the beginning, the boat tends to tip back, so we have all passengers sit on the bow, and it stays level, but it still doesn't have enough power. Could this be a propeller issue, or does anyone have any other suggestions...or is it that this motor just isn't big enough?
Thanks.

[99yam40]

That motor should turn 6K at WOT under normal load, so you are over propped to start out with
pulling a skier puts a load on the motor, so using a different prop (Less pitch)for that type of use is a very good idea

[boscoe99]

It is a propeller issue.

With the boat loaded the engine should be able to turn at or near 6000 RPM WOT.

Try a Yamaha Pontoon series propeller.

Without knowing what propeller brand, model and pitch propeller is in use today it is all but impossible to hazard a guess as to the size you need.

Just know that if and when you are not pulling skiers, and/or the boat is mostly empty, just mind the throttle so as to not let the motor over speed. Just like you do in your car or truck when you are going down a hill.

[Yamaha115OB]

You guys are right...I took it out and at top speed (does WOT mean wide open throttle?) it goes 5900 when it is on the water and the boat speedometer says 35 mph after it is planing. The propeller is a 13 1/4 x 17-K. The fact that the RPM is close to 6000 suggests to me that the propeller is okay, because if the pitch changes, then won't the RPMs go too high or too low? But it takes a long time to get the boat to plane...and that is why it is so hard to get the skier up....it really drags at the beginning of throttling up fast to start the skier. Is the propeller correct or should I change it...and what changes should I make?
Thank you!
If you want to see the boat running on the water with video of the tachometer and speedometer...check out https://www.youtube.com/watch?v=vswriFKaF7Q

[boscoe99]

Life is about trade offs.

You are correct that from a motor standpoint it is fine that the motor is able to turn near 6000 when the throttle is wide open. Which also gives you the best boat speed. For that particular propeller. For just the boat as it is.

But from pulling a skier onto plane the propeller is not the best that it can be. There are other propellers that will be better from that standpoint. Which when at wide open throttle with a skier being towed perhaps also won't let the motor turn more than 6000 RPM. But if the skier falls off then perhaps the motor could turn more than 6000 RPM. It is then your job to not let the motor over speed.

An assumption being that you are trying to pull the skier and get the boat onto plane with the motor fully trimmed down and in. I am an ex slalom water skier from decades ago. When the maximum power was 80. A lot less than the F115. Now I know from experience that if I wanted to keep the boat from getting onto plane I could do that. I could also help the boat get onto plane while pulling be up. The skier should perhaps lean forward a bit more than he is used to. If he is strong enough he could keep a 300 HP motor from getting onto plane.

[DennisG01]

Just to be sure... are you trimmed FULLY down on takeoff?

So, for skiing days, sure - you can put a different prop on there. Drop at least 2" and maybe even go to a 4-blade. Just keep in mind that since your max speed is only 35MPH right now (verify with GPS), you'll pretty much be running WOT all the time when pulling that slalom skier since your max speed is going to drop.

But... Look into "Smart Tabs". I have put those on one of my boats... a bunch of family member's and countless customer boats. They will ABSOLUTELY improve your hole shot with no loss of top end speed. Will give you a better ride in choppy water, too. They really will offer a night and day difference in your hole shot. Inexpensive and only about an hour to install. I would, hands down, install these rather than put a different prop on there.

[99yam40]

A 20 foot boat and a F115 may not be the best package.
what max HP is the boat rated for?

have you tried looking up what prop others used with a boat and motor like yours?

I agree with Boscoe, someone on one ski can help or hurt the boat get them up.
just sitting back and letting the boat do all the work(if enough HP and prop) is not the best way on a marginal HP boat

[pstephens46]

F115 and how many passengers watching the one poor wretched slalom person struggling? Those little 1960s tri-hulls with maybe 2 total in boat were a little different.

[Yamaha115OB]

Anybody else have an opinion on "Smart Tabs"? I've never heard of them, but from what I see on youtube, they can help...but I'm a little afraid of putting some after-market device on there.

[pstephens46]

Anybody else have an opinion on "Smart Tabs"? I've never heard of them, but from what I see on youtube, they can help...but I'm a little afraid of putting some after-market device on there.

After-market is no big deal. Smart tabs are a low cost option to electric or hydraulic trim tabs. Once you have a boat with tabs you can’t live without them. Trust me.... You can level the boat, side to side. Drop the bow for choppy water. Put them all the way down for a quicker plane. Don’t know your financial situation.....consider Lenco electric tabs.

Not 100% on whether the tabs will solve your current issue....

and....I like to see a man stop a f300 powered boat from planing

[99yam40]

Hope this helps you .
it should be close to what your rig is,
I see they list it as a 200 hp rating.

but notice they only had 2 people in the boat and they were not pulling a skier, so probably not the best for pulling a skier.



https://yamahaoutboards.com/en-us/ho...2017-10-11_dck

they list more under deck boats
https://yamahaoutboards.com/en-us/ho...ance-bulletins

have you thought about finding a Hurricane forum to ask what prop to be using for sking?

[Yamaha115OB]

Thanks 99yam40 for the performance bulletins. I found my exact setup at https://yamahaoutboards.com/en-us/ho...r_10-29-09_dck and see that the propeller they indicate is what I have. And, yes, given that the motor is running well, I should probably move to a Hurricane forum. I just really value the info from you guys.

13 1/4 x 17